1. Field of the Invention
The present invention relates to an optical irradiation equipment and an optical irradiation method, and relates particularly to an optical irradiation equipment and an optical irradiation method which are ideal for the dry cleaning treatment of the surface of templates in a nanoimprint device.
2. Description of Related Art
In the manufacture of semiconductor chips and biochips, recently the photo-nanoimprint technology has gained attention as a method by means of which it is possible to produce at lower costs as compared to the known pattern forming method using photolithography and etching.
In the pattern forming method using this photo-nanoimprint technology, a pattern forming material layer is formed on a substrate such as a wafer, on which a pattern is to be formed, by applying a liquid photocurable resin, a template (a mold) on which a pattern being a negative of the pattern to be formed has been prepared is brought into contact with this pattern forming material layer, and in this condition the pattern forming material layer is irradiated with UV rays and cured. Then, a process to detach the template from the obtained layer of cured resin is performed (see JP-A-2000-194142 and US 2008/0090170 A1 (corresponding to JP-A-2008-91782)).
If in this pattern forming method contaminants and the like are present on the surface of the template, defects are generated in the obtained pattern. Therefore it is necessary to perform a cleaning treatment of the surface of the template. For the method to perform the cleaning treatment of the template, the wet cleaning method using an organic solvent or a chemical such as an alkali or an acid is known (see US 2009/0267267 A1 (corresponding to JP-A-2009-266841)). But with this wet cleaning method there is the risk that a part of the template is dissolved by the organic solvent or the chemical and the shape of the pattern is altered. Then, if remains of the photocurable resin or the like adhere to said template when the template is detached from the cured resin layer, it becomes necessary to perform the cleaning treatment of the template every time a pattern forming has been finished. Because quite a long time is necessary for the cleaning treatment, there is the problem of a substantial decrease of the productivity.
In the manufacture of liquid crystal display elements, for example, an optical cleaning treatment device is used as the means for the cleaning treatment of glass substrates (see JP-A-8-236492 (1996)). But with the known optical cleaning treatment devices, the following problems occur when the cleaning treatment of a template is performed. For the templates in the photo-nanoimprint technology, templates from, for example, quartz glass are used, and the temperature control of the templates is extremely important from the aspects of the dimensional stability and the maintenance of the shape of the pattern. But when an optical cleaning treatment of a template is performed by a known optical cleaning treatment device, the template is irradiated with UV rays at the time of the optical cleaning treatment or is subjected to radiant heat from the UV radiation transmission window of the optical cleaning treatment device. Therefore, there is the problem that the temperature of the template increases.